DEFENSIVE COMPOSITE SCORE

By Jon Nichols

Although an individual playerís defensive talents remain one of the hardest things to quantify in basketball, there are already some pretty good statistics in this area. Here at 82games.com there is defensive plus-minus. Other people such as Dean Oliver have developed their own defensive statistics that do a pretty good job of explaining things. However, as the creators and record keepers of any of these stats will tell you, you canít look at any of these individually and expect to know everything.

What Iíve decided to do is combine some of these stats (with a little input and manipulation of my own) and try to increase their universal appropriateness. Like the others, mine is not perfect and must be taken in context with other information to gain any insightful knowledge. .

I have developed a stat I call Defensive Composite Score, or DCS (if youíre a college football fan who hates the BCS, try to ignore the name similarities). It is three different statistics combined into one.

The first system is made up of the raw box score stats you find in the newspaper every day.

The second is the defensive on/off plus-minus statistics you can find here at 82games.com.

The third and final system is Dean Oliver's Defensive rating. It is an estimate of how many points per 100 possessions a player allows. To calculate it requires a complicated formula, one that can be explained in detail in his book Basketball on Paper.

Each of the three parts is weighted equally.

Why did I choose to base DCS on these? Box score stats do a good job of measuring athleticism and activity on defense, and I like to think of them as a way of measuring not only what a player has already accomplished but how good they can potentially be in the future. Plus-minus does a great job of measuring a playerís defensive impact on the court, especially within a playerís role on the team. Defensive ratings reward good defenders on good teams.

The statistic I developed is based on the power of relativity (Iím no Einstein, and this theory is nothing like his). I rank every player in the league based on how they did in these different methods, and combine their rankings to come up with a final ranking. I then convert these rankings into a score based on a scale of 0 to 100 to make things easier to understand.

But enough with the explanations, here are the top 10 and bottom 10 defenders of 2006-2007, based on Defensive Composite Score:

TOP 10 OVERALL

PLAYER

DCS

Tim Duncan

100

Tyrus Thomas

99

Renaldo Balkman

99

Manu Ginobili

99

Robert Horry

98

Kevin Garnett

98

Emeka Okafor

98

Jason Maxiell

98

Paul Millsap

97

Anderson Varejao

97

BOTTOM 10 OVERALL

PLAYER

DCS

Tyronn Lue

0

Jeff McInnis

0

Wally Szczerbiak

1

Stephon Marbury

1

Chucky Atkins

1

Hakim Warrick

2

Eddy Curry

2

Adam Morrison

2

Jarvis Hayes

2

Anthony Johnson

3

Now, for the not-so-happy stuff, the limitations of this statistic. First, the statistics on which DCS was based are not perfect, so this stat canít possibly be perfect either. Secondly, some players just donít do well in certain statistics, and this hurts their rating. For example, Raja Bell does not get a tremendous amount of steals or blocks, so despite a good +/-, he is vastly underrated by DCS. This stat does take into account fouls, so hackers on defense will be rated lower than you expect (although not too much lower). Finally, Defensive Composite Score is just being developed, and can use further tweaking. As I get input from others and play around with the numbers some more, the DCS ratings should become more and more accurate.

In the table below you can see these ratings for every player, sorted by team and DCS.

Now, I must give credit where credit is due. Blocks, fouls, and steals numbers were obtained from Dougís Stats, which can be found here: http://www.dougstats.com. I used the personal foul efficiency stat developed by David Nelson and Damien Walker in their article on 82games.com, found here: http://www.82games.com/dpoy.htm. Plus-minus stats were found at, of course, 82games.com. Defensive ratings, which were developed by Dean Oliver, were obtained from basketball-reference.com

ABOUT THE AUTHORJon Nichols is a junior Sport Management major at the University of
Michigan. He has written articles for NBADraft.net, CourtsideTimes.net,
and Hoopsanalyst.com. When not at school he lives in Miami and is a
huge Heat fan.